Device for testing for traces of explosives and/or drugs

ABSTRACT

An apparatus is provided for detecting whether a person has handled explosives, narcotics or other substances of interest. The apparatus includes a metallic sample collection surface on which a person may place a finger. Upon removal of the finger, the metallic sample collection surface is moved to a desorber. The desorber heats the metallic surface sufficiently to vaporize residue transferred from the person. The vaporized residue then is transmitted to a detector for analysis. The detector also may include a fingerprint reading apparatus for reading the fingerprint of the person and comparing the fingerprint to known fingerprint data.

This application is a divisional of U.S. patent application Ser. No.10/929,915, filed Aug. 30, 2004.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to an apparatus for testing for the presence oftrace amounts of a contraband material on a person.

2. Description of the Related Art

Terrorism risks continue to increase at transportation facilities,government buildings, banks, restaurants, hotels and other locationswhere there is a significant flow of pedestrian or vehicular traffic.

Airlines now routinely screen passengers and employees for explosives.Screening typically is carried out in several stages. For example, allpassages are required to pass through a metal detector and all baggageis required to pass through an X-ray apparatus. However, a plasticexplosive device could be concealed on a person or in a piece of luggagein a manner that might not be detected by a conventional metal detectoror an X-ray apparatus. Even a small amount of a plastic explosive cancause sufficient damage to bring down an aircraft.

Most airports now include apparatus for detecting trace amounts ofexplosives. These devices operate on the principle that small amounts ofthe explosive materials will be transferred to the body, clothing andluggage of people who had handled the explosive. Some detectors employsmall flexible fabric-like traps that can be wiped across a package orpiece of luggage. The trap removes residue from the surface of thepackage or luggage. The trap then is placed in an apparatus, such as anion trap mobility spectrometer, that tests the residue on the trap fortrace amounts of explosive materials. A device of this type is disclosedin U.S. Pat. No. 5,491,337 and is marketed by the GE Ion Track. Thesedevices typically are employed in proximity to the metal detectors, andsecurity personnel will perform screening on some of the passengersbased on a random sampling or based on a determination that thepassenger has met certain criteria for enhanced screening.

The ion trap mobility spectrometer disclosed in U.S. Pat. No. 5,491,337also can operate in a mode for detecting trace amounts of narcotics.Narcotics are illegal and insidious. Furthermore, it is known that manyterrorists organizations fund their terrorism through the lucrative saleof narcotics.

The above-described ion trap mobility spectrometer and similar deviceshave been accepted at airports in view of the notorious efforts ofterrorist groups to attack commercial airliners. The above-describeddetectors have not been accepted widely at other potential targets ofterrorism, including train stations, bus terminals, government buildingsand the like. The screening of personnel entering train stations, busdepots, government buildings and such by the above-described detectiondevices would significantly slow the flow of people into and throughsuch buildings and would impose a significant cost penalty on theoperators of such facilities.

Only a fraction of airline passengers have their baggage checked fortrace amounts of explosives or narcotics using the available ion trapmobility spectrometers and similar devices. Efforts to use such devicesto check all bags for trace amounts of explosives or narcotics wouldimpose greater time and cost penalties on the airline industry.Additionally, explosive detectors typically are used only on luggage andother parcels. An apparatus of this type would not identify plasticexplosives worn by a passenger who had no carry-on luggage.

U.S. Pat. No. 6,073,499 discloses a walk-through detector. The detectorshown in U.S. Pat. No. 6,073,499 operates under the principle that aboundary layer of air adjacent to a person is heated by the person. Thisheated air adjacent a person is less dense than air further from theperson. Less dense air rises. Accordingly, a thermal plume of air flowsup adjacent to a person. Minute particles, including particles ofexplosives or narcotics, will be entrained in this thermal plume of airand will flow upwardly from a person. The walk-through detectordisclosed in U.S. Pat. No. 6,073,499 employs an ion mobilityspectrometer or ion trap mobility spectrometer to detect microscopicparticles of interest that are likely to be entrained in the thermalplume of air flowing upwardly adjacent to a person who walks through andpauses briefly in the detector. The walk-through detector disclosed inU.S. Pat. No. 6,073,499 is very effective for detecting whether a personis carrying explosives or narcotics and whether the person has recentlyhandled explosives or narcotics.

A person who had handled explosives or narcotics is likely to havemicroscopic residue of the explosive or narcotic materials on his or herfingers, and trace amounts of the explosive or narcotic will betransferred to objects that are handled by the person. U.S. Pat. No.5,741,984 discloses an apparatus for dispensing tokens that preferablyare made of PTFE or cotton. The dispensing apparatus is constructed sothat the individual is required to grip the token tightly to separatethe token from the dispensing apparatus. The token then is fed into atoken handler that delivers the token into an ion mobility spectrometerfor analyzing residue that may have been transferred to the token fromthe hand of the person who retrieved the token from the dispenser. Theapparatus shown in U.S. Pat. No. 5,741,984 creates inventory controlproblems associated with the need for having a sufficient supply oftokens and then periodically loading tokens into the dispenser.Additionally, the system disclosed in U.S. Pat. No. 5,741,984 requires aseparate complex dispensing apparatus for dispensing tokens withsufficient resistance for reliably transferring residue from the hand ofthe person retrieving the token. Additionally, a complex apparatus isrequired for handling the token, feeding the token into the ion mobilityspectrometer and then removing the token after analysis. The inventor ofthe subject application has determined that residue of such contrabandwill be transferred from the fingers of the person to an airline ticket,a boarding pass or an identification card. Pending U.S. patentapplication Ser. No. 10/774,003 discloses a detector that identifiesparticles of interest on such a card-like object. Accordingly, thedevice disclosed in pending U.S. patent application Ser. No. 10/774,003avoids problems associated with maintaining an inventory of tokens,dispensing tokens properly from a dispenser, handling tokens in a tokenhandler and then removing the tokens from the token handler.

The above-described products that check for the presence of traceamounts of substance of interest on luggage, tickets, boarding passesand the like generally work very well. However, there continues to be ademand for a small, rapid, reliable and low cost detector for detectingtrace amounts of substances of interest directly on a person. A deviceof this type would be useful at security checkpoints where a person isnot likely to be carrying luggage (e.g., many commuter train stations orbus terminals) and at locations where a person is not likely to have aboarding pass (e.g., government buildings). The above-describedwalk-through portal provides an unobtrusive checking of passengers forexplosives or narcotics without the need to check luggage or boardingpasses. However, these devices are relatively large and relativelycostly. Hence, devices of this type may be inappropriate for somesecurity checkpoints.

Existing security checkpoints also are very labor intensive, and devicesthat could reduce the number of highly trained technicians would bereceived favorably. In this regard, a typical airport securitycheckpoint requires at least four and typically five or six trainedtechnicians. A first employee reviews personal identification cards andboarding passes at the entry to the checkpoint. A second personcoordinates the loading of carry-on luggage and personal effects onto aconveyor for movement through an X-ray scanning device. A third personcontinuously watches the monitor of the X-ray scanning device. A fourthperson controls the movement of passengers through the walk-throughmetal detector while a fifth person remains available for conductingmore detailed screening with a handheld metal detector. Theabove-described explosive/narcotics detection device that employsfabric-like wipes typically is positioned near the outlet end of theconveyor through the X-ray scanning device. As noted above, the smallfabric-like trap is wiped across the surface of the luggage to pick uptrace amounts of substances of interest that may have been transferredfrom the passenger to the luggage. The wipes then are placed in thedetector and analyzed. A sixth technician generally is available toperform this screening and analysis. Alternatively one of the fivetechnicians mentioned above must be redeployed for this screening andanalysis. A more direct approach would be to detect the substances ofinterest directly on the passenger. Most preferably, such detectionwould be carried out without direct human intervention by thetechnicians who operate the checkpoint.

It is assumed that terrorists and other criminals frequently travelwithout carrying explosives, weapons or other contraband. Existingsecurity checks at airports compare the name on a boarding pass to thename on a photo identification card and then compare the passenger tothe photograph. However, there is virtually no checking of the physicalcharacteristics of the passenger to physical characteristics ofsuspected terrorists and criminals. Additionally, there is virtually nochecking of physical characteristics of the passenger to documentedphysical characteristics of the person whose name appears on theboarding pass or photographic identification. There is also no checkingof whether a person with the physical characteristics of the passengerhas traveled previously under a different name.

Devices are available for taking fingerprints of a person and forcomparing the fingerprints to information in a database of fingerprintinformation. Such an apparatus can compare a scanned fingerprint tofingerprints of certain known suspects. Such an apparatus also can storefingerprint data for future reference or analysis. Other apparatus canidentify people by scans of facial features or other characteristics.

Accordingly, an object of the subject invention is to provide a devicefor detecting the presence of substance of interest on a person at asecurity checkpoint.

Another object of the invention is to provide a device that can checkfor the presence of a substance of interest without intrusion on thepassenger by security personnel.

A further object of the subject invention is to provide an apparatusthat can substantially simultaneously check for the presence of asubstance of interest and check the identity of the person at thesecurity checkpoint.

An additional object of the invention is to provide a lightweightrelatively, low cost, small apparatus for checking for the presence ofsubstances of interest on a person.

Still a further object of the invention is to provide a samplingapparatus where the sampling medium is reusable and non-removably partof the sampling apparatus.

SUMMARY OF THE INVENTION

The subject invention is directed to a detector that can be used at asecurity checkpoint to check for the presence of explosives, narcoticsor other substances of interest on a person. The detector includes ahousing and a detecting apparatus within the housing or communicatingwith the housing. The detecting apparatus preferably is an ion trapmobility spectrometer, such as the detector disclosed in U.S. Pat. No.5,491,337, the disclosure of which is incorporated herein by reference.A product of this type is marketed by GE Ion Track under the trademarkITEMIZER 3®. The detector also could be an ion mobility spectrometer,such as the type disclosed in U.S. Pat. No. 5,200,614. Other means fordetecting trace amounts of explosives, narcotics or other volatilesubstances can be employed as the detecting apparatus in the detector ofthe subject invention.

The detector further includes a sample collection assembly forcollecting samples directly from a person at the checkpoint anddelivering the collected samples to the detecting apparatus so that thesamples can be analyzed for substances of interest. The samplecollection assembly can be removed and replaced with another type ofsample collection assembly, such as the sampling apparatus disclosed incopending application Ser. No. 10/774,003.

The sample collection assembly includes a sampling sheet with a targetsection dimensioned and configured to accommodate a thumb, a palm or atleast one forefinger of a person being screened by the detector. Aninstruction panel and/or a speaker may be provided in proximity to thesampling sheet to provide visual and/or audible signals instructing theperson to place a palm, a thumb or at least one forefinger on the targetsection of the sampling sheet and/or to wipe a palm, a thumb or at leastone forefinger across the target section.

The sample receiver may include a housing with a window disposed so thatthe target section of the sampling sheet is exposed at the window. Thesample collection assembly further includes apparatus for moving thetarget section of the sampling sheet from the window to an inlet to thedetecting apparatus. For example, the sampling sheet may be a generallycylindrical drum, a disc, a plate or a belt. The apparatus that movesthe target section of the sampling sheet from the window to the inlet ofthe detecting apparatus may be an electric motor. The sampling sheet maybe deflectable in response to pressure generated by the palm, thumb orforefinger of the person that is being scanned. Removal of the pressure,therefore, may trigger a pressure sensitive switch that activates themotor for moving the target section of the sampling sheet from thewindow to the inlet of the detecting apparatus. Slots may be provided inthe sampling sheet to facilitate deflection.

The sample collection assembly may include a desorber and a transfer boxin proximity to the inlet to the detecting apparatus. The target area ofthe sampling sheet may be advanced into the desorber. The desorber heatsthe sampling sheet sufficiently to vaporize material transferred fromthe hand to the target area of the sampling sheet. A vacuum pump thendraws the vaporized material into the inlet of the detecting apparatus.The detecting apparatus functions to identify substances of interest andgenerates a signal when a substance of interest has been detected.

The sample collection assembly may further include a fingerprintscanning device for scanning and reading the fingerprint as finger iswiped across the target area of the sampling sheet. The fingerprints canbe stored for future reference. Alternatively, the fingerprint can becompared to known fingerprint data for comparing the scanned fingerprintto other identification information pertaining to the person at thedetector. Alternatively, the scanned fingerprint data can be compared toan existing database with fingerprint data for potential terrorists orother criminals. Information obtained by the fingerprint scan cangenerate an audible or inaudible alarm and can trigger an increasedlevel of scrutiny at the checkpoint.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a detector that incorporates theapparatus of the subject invention.

FIG. 2 is a schematic view of an ion trap mobility spectrometer of thedetector shown in FIG. 1.

FIG. 3 is a front perspective view, partly in section, of a modularsample collection assembly of the detector for detecting substances ofinterest on a finger of a person.

FIG. 4 is a rear perspective view, partly in section of the modularsample collection assembly shown in FIG. 3.

FIG. 5 is a perspective view of a drum for use in the modular samplecollection assembly of FIGS. 3 and 4.

FIG. 6 is a front perspective view of the inlet disposed between thedrum of FIG. 5 and the detector of FIG. 2.

FIG. 7 is a rear perspective view of the inlet shown in FIG. 6.

FIG. 8 is a perspective view of an alternate sample collection assembly.

FIG. 9 is a perspective view of another alternate sample collection.

FIG. 10 is a perspective view of the detector with an alternate samplecollection assembly mounted therein.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A detector according to the invention is identified generally by thenumeral 10 in FIG. 1. The detector 10 includes an outer housing 11 and aflat panel display monitor 12 such as an LCD monitor. An ion trapmobility spectrometer (ITMS) is disposed within the housing 11 and isillustrated schematically in FIG. 2.

The ITMS of FIG. 2 comprises a cylindrical detector 20 having an inlet22 at one end for receiving sample air of interest borne by a carriergas which that has been doped with a low concentration vapor (typicallya few parts per million) employed as a charge transfer mediator. Moreparticularly, the inlet 22 communicates with a source of sample air ofinterest 14 and a supply of carrier gas and dopant 16 with flows ofgases to the inlet 22 being enabled by a flow generator such as a pumpillustrated schematically and identified by the numeral 18 in FIG. 2. Aheated membrane 19 formed from a microporous refractory material or fromdimethyl silicone is disposed near the inlet 22 and in communicationwith the source of the sample of air 14 for blocking passage of at leastselected constituents of the air and for enabling passage of otherconstituents of the air, including the constituents of interest. Thesample air, carrier gas, and dopant molecules pass through the inlet 22and are spread by a diffuser 24 into an ionization chamber 26. Theionization chamber 26 is in the form of a shallow cylinder with adiameter D, length L, and cylindrical wall 28 of a radioactive material,e.g., nickel⁶³ or tritium, which emits beta particles. Inlet 22communicates with one end of the ionization chamber 26. A grid electrodeE₁ is provided at the end opposite the inlet 22, and is normallymaintained at the same potential as the inlet end and the walls of theionization chamber 26. Thus a largely field-free space is provided inwhich electrons and ion charges build up and interact with the samplemolecules under bombardment by the beta-particles from the radioactivewalls. Beyond the ionization chamber 26, the ionized sample gases passthrough open electrode E₁ and into an ion drift region 30 having severalfield-defining electrodes E₂-E_(n). A collector electrode or plate 32 isdisposed at the end of the drift region 30 for receiving the ion samplesreaching that end.

Periodically a field is established across the ionization region 26, bycreating a potential difference between the grid electrode E₁ and theinlet diffuser 24 and radioactive source 28, for about 0.1-0.2 mS, tosweep the ions through the open grid E₁ into the drift region 30 withthe assistance of the switching of the field between electrodes E₁ andE₂. The ions in the drift region 30 experience a constant electricfield, maintained by the annular electrodes E₂-E_(n), impelling themalong the region and down toward the collector electrode 32. Theelectrode 32 detects the arriving charge, and produces signals that areamplified and analyzed through their spectra in the spectrometer. Thegases exit through an outlet in the wall next to the electrode 32. Afterabout 0.2 mS the field across the ionization region 26 is again reducedto zero and the ion population is again allowed to build up in thechamber 26 preparatory to the imposition of the next field. The polarityof the fields is chosen on the basis of whether the detector is operatedin a negative or positive ion mode. When detecting explosives, anegative ion mode is usually appropriate, but when detecting narcoticsamples positive ion mode is preferred.

The detector 10 includes a sample collection apparatus that isidentified generally by the numeral 40 in FIGS. 1 and 3-7. The samplecollection apparatus 40 include a housing 42 that can be mountedremovably into a receptacle 44 formed in the housing 11 of the detector10. More particularly, the sample collection apparatus 40 is a modularunit that can be releasably mounted to the housing 11 of the detector 10so that the detector 10 can be adapted for a particular use. In thisregard, the sample collection apparatus 40 can be removed and replacedwith another sample collection apparatus, such as the card samplingapparatus as identified generally by the numeral 70 in FIG. 10, and asdisclosed in copending application Ser. No. 10/774,003. Alternatively,the sample collection apparatus 10 can be replaced with the knownapparatus for receiving a fabric-like trap that may be wiped across asurface of a parcel or piece of luggage to detect substances ofinterest.

The housing 42 of the sample collection apparatus 40 includes a window46 at a position on the housing 40 that will face the person that is tobe scanned for trace amounts of substances of interest. The window 46 isconfigured and dimensioned to receive substantially all of the grippingsurface of the distal digit on a thumb.

The sample collection apparatus 40 further includes a generallycylindrical drum 48 mounted in the housing 42 for rotation about an axisthat is parallel to the front face of the detector 10. Moreparticularly, the cylindrical drum 48 is disposed to be substantiallyinternally tangent with portions of the housing 42 adjacent the window46. Hence, a target area on the exterior of the drum 48 will be exposedat the window 46. The drum 48 is formed from a material that will retainresidue from the hand of a person being screened. The material of thedrum 48 also must be able to be heated quickly and repeatedly tosufficiently high temperatures for vaporizing residue received from thehand. Additionally, the material of the drum 48 should be capable ofbeing cooled quickly to prevent discomfort when a finger is placed onthe drum 48 and to maintain a desirably low cycle time for scanning. Thematerial of the drum can be a non-metallic material or a thin metallicmaterial, such as aluminum or stainless steel. Aluminum exhibitsdesirable heating and cooling characteristics and exhibits a long life.The thickness of the material of the drum 48 also is selected tofacilitate rapid heating and cooling. A thickness in the range of0.002-0.020 inch is preferred. The relatively thin material of the drum48 also permits slight inward deflection of the drum 48 in response todigital pressure created by a thumb or forefinger placed on or wipedacross the target area of the drum 48 exposed at the window 46. Thisdeflection can trigger a pressure sensitive switch to activate ascanning cycle.

The drum 48 further includes a plurality of slots 50 that extendentirely through the material of the drum 48. The slots 50 performseveral functions. The slots 50 remove mass from the drum 48 and breakthe conductive heat transfer path to facilitate rapid heating andcooling of the drum 48. The slots 50 also accommodate air flow tofacilitate cooling. Additionally, the slots 50 facilitate deflection ofthe drum 48 that may trigger the pressure sensitive switch. Slots 50that are aligned parallel to the axis of the drum 48 permit theapparatus 40 to accommodate the optional fingerprint scanning. However,embodiments without the fingerprint scanning option can have slotsoriented differently or can have perforations other than slots.

The sample collection apparatus 40 further includes a pressure sensitiveswitch 52 fixedly mounted to the housing 42 at a location radiallyaligned with the window 46 and inwardly from the drum 48. The switch 52senses small deflections of the drum 48 as the thumb or forefinger iswiped across portions of the drum 48 in the window 46. Thus, the switch52 can generate a signal to activate a scanning cycle.

A fingerprint reader 54 optionally is disposed inwardly of the drum 48for reading fingerprint characteristics of a thumb as the thumb is movedrelative to the slot 50. Alternatively, the switch can include anoptical switch that will sense the presence of light that occurs whenthe thumb is slid past the slot 50 and into a position where ambientlight can again enter the slot 50.

The sample collection apparatus 40 further includes a motor 56 mountedto the housing and operative to rotate the drum 48. The motor 56 isconnected to the switch 52 and functions to rotate the drum 48 aselected amount in response to the sensed completion of a wipe of athumb or forefinger across portions of the drum 48 disposed in thewindow 46.

The sample collection apparatus 40 further includes a desorber 58mounted to the housing and disposed interiorly of and adjacent to thedrum 48. The desorber 58 functions to rapidly heat portions of the drum48 aligned with the desorber 58 for vaporizing trace amounts of materialtransferred from the thumb or forefinger to the target area of the drum48 that was exposed at the window 46. The desorber 58 preferably isalways on when the detector 10 is on to avoid a need for preheatingduring each scanning cycle. A sample transfer box 60 is mounted to thehousing 42 at a location radially aligned with the desorber 58 butdisposed exteriorly of and substantially adjacent the drum 48. Thedesorber 58, and the sample transfer box 60 have opposed facing surfacesthat are curved with radii of curvature substantially corresponding tothe inner and outer circumferential shapes of the drum 48. The sampletransfer box 60 further includes a sample tube 62 that communicates withthe inlet 22 of the ion trap mobility spectrometer of FIG. 2.

The apparatus 10 is employed by providing audible or optically readableinstructions to a person who desires access to a restricted or securedarea. The optically readable instructions may be provided on the displaymonitor 12. In particular, the person will be instructed to wipe a thumbacross the target area of the drum 48 exposed at the window 46. Thefingerprint reader 54, if provided, will optically scan the fingerprintas the thumb is wiped across the slot 50 in the drum 48. The fingerprintdata can be stored for future reference. Alternatively, the fingerprintdata can be used to compare personal identification informationassociated with the fingerprint to other personal identificationinformation presented by the user. For example, the identity of theperson determined by the fingerprint scan can be compared with identityon an identification card or boarding pass that also is presented to theapparatus 10. An incorrect match may generate a signal to instruct ahuman security technician to conduct enhanced checking to determine thecause of an inconsistency. Alternatively, the scanned fingerprint datacan be compared to known databases that have fingerprints for suspectsof terrorism or other crimes. A match with these known databases cangenerate an audible or inaudible alarm that will trigger additionalscreening by security personnel or by other available equipment at asecurity checkpoint.

The movement of a thumb across the target area of the drum 48 exposed atthe window 46 will deflect the thin aluminum of the drum 48 and willactuate the pressure sensitive switch 52 aligned with the window 46.Alternatively, a switch can detect changes in light level as the thumbmoves clear of the slot 50. The signal generated to indicate acompletion of a wipe of a thumb across the target area of the drum 48 inthe window 46 will cause the motor 56 to rotate the drum 48 an amountother than 180°, and preferably about 135°. Thus, the target area of thedrum 48 that had been aligned with the window 46 will advance into thenarrow space between the desorber 58 and the sample transfer box 60. Themotor 56 then stops. The heated desorber 58 raises the temperature ofthe drum 48 between the desorber 58 and the sample transfer box 60sufficiently to vaporize residue transferred from the thumb to the drum48. A vacuum pump 18 in the detector of FIG. 2 then will draw thevaporized material through the sample collection tube 62 and into thedetector for analysis. The ITMS will detect the presence of substancesof interest and will generate an appropriate signal for additional orenhanced testing by security personnel at the checkpoint. The ITMS alsocan check for “people peaks” indicative of a human being. The absence ofa “people peak” may suggest that a person is wearing gloves or hasplaced a pen or other inanimate object on the drum 48 to avoid anaccurate scan. The absence of a people peak may generate a signal foradditional screening. The preferred 135° rotation of the drum ensuresthat the area of the drum 48 that was most recently heated by thedesorber 58 will not be rotated directly back into alignment with thewindow 46. Thus, target areas on the drum 48 are more certain to besufficiently cool when aligned with the window 46.

The sample collection apparatus can take other configurations. Forexample, FIG. 8 shows a sample collection apparatus 40A with a drum 48Amounted for rotation about an axis aligned at an angle, and preferably aright angle, to the front face of the detector 10. The window 46A issufficiently wide to place all forefingers of one hand on a portion ofthe drum 48A exposed at the window. FIG. 9 shows a detector 40B with analuminum disc 48B in place of the drum. The disc 48B rotates about asubstantially vertical axis. Other options can include a thin plate thattranslates without rotation or a flexible belt that is driven aboutrollers.

While the invention has been described with respect to a preferredembodiment, variations can be made without departing from the scope ofthe invention as defined by the appended claims.

The illustrated apparatus shows the sample collection apparatus 40 asbeing a modular unit in the detector 10. The sample collection apparatuscan be removed and replaced by a card scanner 70, as shown in FIG. 10and as disclosed in copending application Ser. No. 10/774,003.Alternatively, an apparatus for receiving fabric-like sample traps canbe inserted in the receptacle 44. However, the sample collectionapparatus 40 can be part of a dedicated detector apparatus without anability to convert to other testing formats.

The illustrated embodiment of the detector shows a monitor 12 facinggenerally in the same direction as the window 46. However, the monitor12 can face in the opposite direction so that a security screener canobserve the monitor from one side of the apparatus while a persondesiring security clearance will be on the opposed side of theapparatus. Alternatively, a monitor can be disposed at a remote locationor can be replaced by or supplemented with other signal generators forindicating clearance or a need for further checking. One monitor can beused to assess scanning performed by a system of detectors 10.

The sampling sheet can be formed entirely from a metallic material, anon-metallic material or combinations of metallic and non-metallicmaterials. For example, the sampling sheet can include a metallicsupport at peripheral locations on the sheet and a non-metallic materialat intermediate positions.

1. A modular detecting system comprising: a housing, a detector in thehousing for analyzing a sample to determine whether the sample containsany substances of interest, a first sample collection apparatusconfigured for receiving a sample residue from a portion of a hand of aperson and selectively placing the sample of residue in communicationwith the detector for analyzing the sample of residue collected directlyfrom the person and a second sample collection apparatus configureddifferently than the first sample collection apparatus and having anopening for receiving at least a portion of an object and selectivelyplacing a sample collected from the object in communication with thedetector for analyzing the sample from the object.
 2. The system ofclaim 1, wherein the first sample collection apparatus includes a drumfor receiving contact from part of a hand and a motor for moving thedrum into a position for transferring material from the drum to thedetector.
 3. The system of claim 1, wherein the second sample collectionapparatus includes a slot for receiving the object, which objectcomprises a card, and for removing residue from the card for analysis bythe detector.
 4. A modular detecting system comprising a housing, thehousing being formed with a receptacle, a detector in the housing foranalyzing a sample to determine whether the sample contains anysubstances of interest, the detector having an inlet disposed in thereceptacle for receiving the sample, a first type of sample collectionapparatus selectively and removably placeable at least partly in thereceptacle and a second type of sample collection apparatus selectivelyand removably placeable at least partly in the receptacle, the secondtype of sample collection apparatus being configured differently thanthe first type of sample collection apparatus, the first and secondtypes of sample collection apparatus each having a sample outlet tubethat communicates with the inlet of the detector when the first orsecond type of sample collection apparatus is in the receptacle, whereinthe first type of sample collection apparatus is configured forcollecting a sample directly from a hand of a person, and wherein thesecond type of sample collection apparatus is configured for collectinga sample transported by an object other than a person, whereby the firsttype of sample collection apparatus can be removed from the detector andreplaced by the second type of sample collection apparatus.